Thermal cut-out.



No. 854,724. PATENTED MAY 28, 1907. J. T. H.- DEMPSTBR.

THERMAL GUT-OUT; APPLICATION FILED 'Nov.'1.19o4.

Fig. 2..

Witnesses. I Inventor: WM! 5 J0hnTH.D empst h JVW-Q Q Hu u- STAEEATENT OFFICE.

new; in; DEMPSTER, OF scriENEcrADY, {NEW YORK, ASSIGNQR TO. GENERALELEGIRICCQMBANSLTA CORPORATION OENEW YORK.

' THERMAL GUT-OUT.

fa: citizenbf the U-mted States, residing at gschene'ctadi county .of Schenectady; State 7 The-presentinvention.relates to cut-out:

'1' devices for interrupting electrical circuits gerous -currents'; and-more 'p'articularl to cles 'oflmolten-metal fro'rn scattering and igniting combustibles in-its'vicinit y,

p In thefuses' designed for the protection of go circuits carrying currents 'of considerable vol ume the fusible strip isso large that upon .blowing .a very" great volume of gas .is

evolved'which' frequently explodes? the aim numerous attempts dense-the gases-or to confine the fusion to a .short section of the iuse strip-jsdthat the pressure; due to evolved gas'ealwill not ap- --an.- iiiclosed fusein which-the amount of "metal upon blowing will be restricted t and the gases evolved therequickly and effectually condensed. In carryin' out iiny invention'l provide a suitable envelop with aplurality of insulated metal plates arranged in proximity toithe fusible stri' so that-the are which forms up on blowing w lbelfsubdiyided into anumber of Smaller ones eitendin'g-fmm plate to plate land the sum of the counter-electr0m0tive forces of these small arcsthereby made efi'ect-' 've inpre'venting the extension of the fused V v ticular formor arrangementlof. partsherein section beyond a limited number of plates,

I the use strip be condensed'upon coming in contact with the surfaces of the" heat conduqting metal P t s:

For a more complete understanding of my invention'reference may b'e -made. to the following detaileddescriptionjand the accomapart of this :spec ication, invvhic have inventedcertaiii new and;

. metal. end caps Zsepiured'thereto by-sorews upon the passage thereof of abnormal or danthat-type'offeut-outs know-n asiiiclosed ses E ndingthro the base. of the, tube 1.

which consist of a strip-' of. fusible {pietaladapted-to be connected in'the circuit-to be pifotgctediand inclosed by a stoutitubeor boxto prevent-the volatile gases and the parti-.

velep,;and in order 'to' prevent this action.

' have been madeto con-- and the gases evolyedby the fused section. of

- Patented. ma 28,'1"9jo7..

=br o'k en away-showing one 'forr'niof mfyinven- -tion;; .and 2- -fis'ra transverse ,section thcreoi'." e I The casingisof iordinary construction con-3 sisting' of'an' insulating-tubelprovidediwith 6o 3- and' having contact blades'zfi extending through-their ends and hjldjin placeby out-' "wardlybe'nt'lugs 5 andipins {6 on opposite sidesofthe shell ends. Y i

-6 is a series of" transversely arranged metal 5 plates 7 which are heldjequallyspaced by in-. 'sulating rings 8; fitting the'iniler periphery of ;the t be; These plates are each-provided. with a 'LchOrdal slot 9 and whenas'seinbled they are arranged sethat the slots iii-alternate plates will lie on opposite sides of. the axis, as shown in Fig. 1. The fusible strip 10 extendslin 'a zigzag pathlacross the. spaces between the "plates and through the slots 9- in themand the ends are connected to the respectivewntacts 4h Upon the blowingofa'fuse constructed'as above described a's'hort arc-is first foi'med across the" space previously occupied by the weakestpoint, in the fuse strip and immed.i ately extends; itself in opposite directions by volatilization of the severed ends of the stri and iii-passinglfrom plate to late' it siib vides itself intoaseries of sfma arcsuntil the sum of the eounter-electromotive forces of the small ares is sufficient to oppose-further extension of the arcing action, and the gases evolved from. the section of the fused strip" being brought into contact with the surfaces of the heat conducting plates 7 are quicklycondensed so that the pressure on thewalls I of the sliellis prevented frem becoming e'x- 'cessive and the arcis quickly-deprived of itsi s11 porting medium.- 9 5 ldo not desire 'to'restrict myself to therpardescribed and shown;- since it is apparent that they may be -changed and modified withoutdeparting from my invention. I jibo pW'hat I claimjas new and desire to secure .b LettrsPat-ent 'ofthe'United States," is, 1. An electric fuse c'ompris'ing'a fusible stri and means to subdivide the electric arc an condense the gases of fusion arranged in lo 5 proximity thereto.

2. An electric fuse comprising a fusible strip, and one or more independent metal piecesarranged in proximity thereto and adapted to subdivide the arc and condense the gases of fusion. I

, 3. An electric fuse cqm ri'sin a fusible strip, and a series of in epen ent metal pieces engag ng said strip and supportinglit lnasinuous position.

4. An electric fuse com IlSlD. a fuslble strip, and a' series of in epen ent metal plates provided with slots in which said striphand this 4th lllLlllLS,&I1(i a fusible strip extending through and substantially filling said apertures.

7. An electric fuse comprising an inclosing shell, a series of independe metallic plates provided .With eccentric .a ertures and arranged transversely of sai shell with said apertures disalined, and a fusible strip extending through said disalined aperture'si 8'. An electric fuse comprising an inclosing shell, a series of metal plates provided with eccentric apertures and arranged transversely of said shell with the apertures in alternate plates on opposite sides of the axis. insulatingrings separatin said lat-es, and a fusible strip extending t ouglE tures. I

In Witness whereof I have hereunto set my day of November, 1904'.

, JOHN T. H DEMPSTER. Witnesses:

BENJAMIN B. HULL,

HELEN ORFORD.

said apei 

